Which site really leads to more marriages? It’s hard to say. According to a 2013 Pew Research report, Match.com is easily the most popular dating site, with 45% of online daters saying they’ve used Match.com against 23% who’ve used eHarmony. But that doesn’t necessarily mean Match.com leads to more marriages. Perhaps everyone who signs up for eHarmony winds up happily married, and only half the folks using Match.com do.

But although it’s not clear cut, it still seems likely that Match.com — simply by being more popular — leads to more marriages than any other site. The PNAS study found only a small difference in the number of marriages coming from eHarmony and Match.com (25.04% of marriages where the couple met online came from eHarmony, vs. 24.34% for Match.com). And the Chadwick Martin Bailey study found that Match.com was responsible for 30% of the online marriages, against 15% for the next-closest site.

Our advice? The companies should get together and commission one more study, winner take all.

But that won’t happen, because someone will lose. So for now, take everything you hear in a commercial for a dating website with a grain of salt. No site has yet proved it leads to more marriages than any other site.